1. Field of the Invention
The present invention relates to a gyratory compactor apparatus and, more particularly, to an improved gyratory compactor apparatus and associated devices and methods.
2. Description of Related Art
In order to measure certain physical properties, such as density, moisture content and compressive strength, of some materials, such as soil or paving material, loose samples of the soil or paving material are formed into test specimens under reproducible conditions using laboratory compaction machines. It is desirable to compact the test specimens under conditions that simulate actual use. For a paving material sample, this requires simulation of the kneading force applied to the paving material by the paving roller. Simply applying a compressive force to the sample does not adequately simulate the kneading action of the paving roller. As a result, compaction machines that gyrate the sample during compression have been developed to simulate actual conditions of use.
For example, a compaction machine which provides axial compression while gyrating the sample of soil or paving material so as to effectively knead the sample is illustrated in U.S. Pat. No. 5,323,655 to Eagan et al. The gyratory compactor described therein includes a ram applying compressive force from one end of a cylindrical mold, wherein the other end of the mold is gyrated by rotating a base supporting the other end of the mold.
Another example of a gyratory compactor apparatus is disclosed in U.S. Pat. No. 5,939,642 to King et al. The '642 patent describes a gyratory compactor apparatus design for facilitating ergonomics and efficiency, while improving consistency of operating parameters. The gyratory compactor described therein allows the user to slide the cylindrical compaction mold into the compaction chamber without the necessity of lifting the mold and includes an integral specimen removal ram. In addition, the frame design reduces frame deflection that could undesirably affect the angle of gyration. Further, the angle of gyration of the compactor apparatus can be changed by simply replacing a single component of the apparatus.
Notwithstanding the advances that have been made in the art of gyratory compactors, there is a need for smaller and less costly designs, with improved operational efficiency and accuracy. Additionally, there is a need for a gyratory compactor having improved ergonomics. For example, placement and removal of the mold containing the sample should be accomplished with minimal difficulty. Also, it would be advantageous to provide a compactor design that allows the user to quickly and easily change operating parameters, such as the angle of gyration. Further, there is a need in the art for a gyratory compactor that provides a constant angle of gyration during the compaction procedure with minimal deviation therefrom.